A 14-year-old Streatham girl stabbed a “dirty paedophile” to death who she said abused her and her sister, a court was told.

The girl, along with her sister’s boyfriend – a 14-year-old from Clapham – stabbed Robert Daley five times in his kitchen just an hour after discovering he would not face prosecution for a string of alleged sexual assaults, the Old Bailey was told on Tuesday.

Police had investigated claims of sex attacks on her 16-year-old sister and another woman but had dropped the case because of a lack of evidence, the court heard.

The Streatham girl also claimed Mr Daley sexually abused her from the age of 12, but prosecutors never looked at the case because she had not made a formal statement, the court was told.

The two alleged killers went to Robert Daley’s flat in Ferndale Road, Brixton, shortly before 6pm on April 23 this year, after the elder sister telephoned them to say the police had dropped the case.

Mr Daley had rung to tell her the news, the court heard.

The older sister sent Mr Daley a text message minutes later saying: “You are a perverted man and I will never forgive you”.

Jonathan Rees, prosecuting, said the telephone call was the “catalyst that motivated them to pay him a visit”.

The two teenagers met and travelled together to the flat, banged on the front door and called out to Daley, before being let in the kitchen, the court was told.

Mr Rees said they could have been let in because “relationships were relatively cordial in the weeks before the murder”, despite the allegations.

Allegedly they had dinner together the week before the killing, the court heard.

It was after the two teenagers were let in that the “sustained attack” occurred, Mr Rees told the jury.

Two blows from the knife penetrated Daley’s heart, causing massive blood loss and subsequent death,” the court was told.

He came crashing through the living room door before collapsing in a pool of blood in front of a female friend, the jury heard.

The two teenagers were seen running from the block of flats by a passerby who heard screaming.

The court was told CCTV showed they had been in the block for just eight minutes.

Mr Rees told the jury he understood the boy would claim he used the knife on My Daley to defend himself and the girl from attack by the man.

Mr Rees said the girl told police they had gone to the flat to “hustle” some money from Mr Daley, but the “dirty paedophile” had tried to grope her and the boy had “stabbed Daley in helping her get away.”

But Mr Rees told the jury she had told friends later that day she had stabbed him.

The boy is alleged to have later told a friend “he had got himself in a lot of trouble”.

His handprint in Daley’s blood was found on the communal doorway to the housing block’s stairwell, the court was told.

The passerby said she saw the boy tossing an object, which the prosecution alleged contained the bloody knife used to carry out the attack, into a wheelie bin, before the girl shouted “don’t be stupid”, pushed over the bin, grabbed the bag and continued to run off.

She later asked a friend to look after the knife for her, the court was told.

She told police after the incident she was “scared and frightened” and covered in blood and later threw the blade into bushes and burnt her clothes, the court was told.

They were arrested and charged within days of the killing. Both deny murder. The trial, scheduled for two weeks, continues.